Thursday, May 17, 2007

Back to the Sixties

Now

Partly sunny, cool. Following yesterday's cold frontal passage, northerly breezes and some persistent clouds from a weak trough in the Ohio Valley have kept temperatures about 15° cooler this afternoon; most places are maxing out in the upper 60s.

Strengthening of the upper-level trough is likely to keep cooler temperatures and the possibility of showers in the area into at least part of the weekend.

Map of yesterday's rainfall from the NWS experimental precipitation analysis shows some amounts over half an inch (shades of green) mainly south of the District. Through much of Northern Virginia and the northern suburbs, however, amounts were below 0.25" (lighter shades of blue).

Tonight and Tomorrow

Mostly cloudy, cool, chance of showers. Low temperatures under mostly cloudy skies will be in the low to mid 50s tonight. Tomorrow will be mainly overcast with a 60% chance of showers, especially to the south and east of the metro area, and highs only 59-63°.

For the outlook through the weekend and beyond with Larson's Long-Range, scroll on down to Josh's post below.

Climate Corner: Seeing the Forest or the Trees?

Thanks to an extensive cold spell in April, some people (including some professional meteorologists who should know better), have been implying that global warming is not a concern because "everything averages out." It's true that about 1200 daily low temperature records were set in the U.S. during the record cold outbreak of April 4-10. However, climate is not a subjective interpretation of extremes, and global climate is not determined only by what happens where most people (or even most meteorologists) live.

NOAA reported yesterday that, despite the extremes, April was near average for the U.S. overall. Globally, surface temperatures were the third warmest on record, and for the January-April period they were the warmest ever observed. Looking only at land locations, April temperatures were also the warmest on record. Nearly all of Europe averaged above average, with large portions of France, Switzerland, Germany, and Austria 9°F or more above average. Extensive warmth was also seen in Argentina and Brazil.